A casting defect where alloying elements distribute unevenly over distances ranging from centimeters to meters during solidification. It occurs because solute-rich liquid moves through the solidifying dendritic network due to thermal contraction, gravity or convection currents. Unlike microscopic segregation, these large chemical gradients cannot be fixed by homogenization heat treatments and permanently affect the mechanical properties of the final part.
Heard on the job
We found severe macrosegregation in the center of the billet, meaning the carbon content is way out of spec.
Do not mix it up with
- Microsegregation: Microsegregation happens between individual dendrite arms and can be fixed by heat treatment, while macrosegregation spans the whole casting and is permanent.